Conventionally, in active-matrix flat-panel displays (FPD) such as liquid crystal displays or organic electroluminescence (EL) displays, thin-film semiconductor devices also referred to as thin-film transistors (TFT) have been used.
Generally, in the thin-film semiconductor device, as a TFT that can realize a low cost, a bottom-gate TFT is used where a gate electrode is located closer to the side of a substrate than a channel layer (semiconductor layer) (Patent Literature 1).